n-3 Fatty acids have been shown to modify several key risk factors for cardiovascular disease. However, it is not clear whether the apparent protection against
cardiovascular disease is directly related to antiatherogenic functions of these
fatty acids or is mediated through their modification of the risk factors through mechanisms not directly related to
lipids. A major question concerns the importance of
lipid modification, which is a potent outcome of
fish-oil supplementation. On balance,
lipid modification is likely to represent a significant antiatherogenic factor. The benefits include increased HDL(2)-cholesterol concentrations, reduced
triacylglycerol-rich
lipoprotein concentrations, reduced postprandial
lipemia, and reduced remnant concentrations. In contrast,
LDL-cholesterol concentrations have often been noted to rise and the potential of increased oxidizability of LDLs is potentially adverse with
lipid modification, but this potential can be overcome with
vitamin E supplementation. The characteristic
lipid changes and the underlying mechanisms are reviewed. Additional benefits of
fish oils include improved endothelial function and better arterial compliance (elasticity). Future trials will be needed to determine minimum effective dosages of eicosapentaenoic and
docosahexaenoic acids over lengthy periods and to show
cardiovascular disease reduction through intervention.